The electric arc furnace is a good melting reactor, but presents certain metallurgical restrictions, mainly regarding the refining of low impurity level steels. These limitations are due to the almost complete absence of agitation of the molten bath. It is known that if the molten bath is stirred, the heat and mass transfer rates are increased to approach faster the equilibrium conditions in the slag-metal-atmosphere system.
In that regard, some plants are using electromagnetic stirring, however, the power agitation with this process is limited.
It has been proposed to stir some metallurgical vessels like converters by bottom gas injection. This practice has certain technological restrictions when used in the electric arc furnace: With common refractory permeable elements used in converters, it is not possible to cut off the gas flow; on the other hand, if the molten bath in the electric arc furnace is strongly stirred, the ejection of molten bath can occur through the furnace charging door.
The main gases used as stirring gas are argon and nitrogen. Natural gas has been used only for the following purposes: copper deoxidation by injection of reformed natural gas; cooling of the oxygen injection tuyeres; and to transport powders in the pig iron desulfuration.